1. Field of the Invention
The present invention relates to a novel polymer which has functionality as a detergent builder. More specifically, the terpolymer is derived from acrylic acid monomers, maleic acid monomers and 2-sulfoethyl methacrylate monomers.
2. Technology Description
A detergent builder is an inorganic or organic salt (in solid form) which provides detergency by chelating the heavy metal ions present in water used to wash fabrics. Known builders include phosphate salts and citrate salts, with sodium citrate being a preferred builder salt.
Polymeric materials have also been suggested as detergent builders. Examples of such materials include those derived from acrylic acid. Specific examples of such polymeric builders include those described in U.S. Pat. No. 5,175,361. According to this publication a polymer useful as an encrustation inhibitor is prepared by copolymerizing by free radical polymerization acrylic acid and maleic acid or acid anhydride monomers. The reference further suggests that up to 10 percent of a noncarboxylated alkene may be additionally polymerized with the monocarboxylic and dicarboxylic monomers. Examples of noncarboxylated alkenes include the following materials: acrylamide, methacrylamide, acrylamidosulfonic acid, vinylsulfonic acid, allylsulfonic acid, vinylphosphonic acid, allylphosphonic acid, vinyl acetate, hydroxyethyl acrylate, hydroxypropyl acrylate, vinylglycol, methyl acrylate and methyl methacrylate.
Other patents which suggest the use of acrylic based materials as detergent builders or dispersants include U.S. Pat. Nos. 5,077,361; 4,621,127; 4,681,686; 5,216,099; 5,256,746; and 5,294,687.
Chemical Abstracts Registry Number 86458-33-5 discloses a polymer formed by the reaction of 2-(Z)-butenedioic acid with 2-propenoic acid and sodium ethenesulfonate.
Despite the above teachings, there still exists a need in the art for a superior polymeric builder material which demonstrates excellent redeposition properties.